Chemicals released into surface and subsurface waters can be a pervasive environmental problem. Sources of chemical contamination can range from improperly disposing of and/or treating of chemical waste, abandoned waste disposal sites, leaking storage tanks, mining and the like. Chemical contaminants can include oxyanions which can be difficult to remove from contaminated waters, soils, and the like due to the oxyanion's kinetic and thermodynamic properties. Oxyanions are defined as a chemical compound with the generic formula AxOyz− where A represents a chemical element and O represents an oxygen atom. Oxyanions of particular concern in the environment include perchlorate, sulfate, sulfite, nitrate, nitrite, arsenate, arsenite, chromate, thiosulfate, polysulfides, polythionates, hexathionate, pentathionate, tetrathionate, trithionate, dithionate, bromate, bicarbonate, carbonate, uranyl carbonate, vanadate, selenate, silicate, selenite, and/or mixtures thereof. Anions of concern could also include bromide, chloride, fluoride and sulfide.
In fact, perchlorate has become a significant environmental contaminant with conventional treatment techniques such as the use of virgin granular activated carbon, air stripping, and advanced oxidation having limited or no effect in removing low perchlorate concentrations from water. Sulfates can also be a problematic contaminant, e.g. high sulfate concentrations are known to be present in acid mine drainage water. Therefore, a material and/or process that can remove low perchlorate and/or sulfate concentrations from water would be desirable.